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    2 vulnerabilities found for OpenApi.YamlReader by Microsoft

    CVE-2026-72923 (GCVE-0-2026-72923)

    Vulnerability from nvd – Published: 2026-09-08 17:12 – Updated: 2026-09-08 17:53
    VLAI
    Title
    Microsoft.OpenApi.YamlReader/Readers vulnerable to denial of service via YAML alias expansion
    Summary
    In Microsoft.OpenApi.YamlReader from 2.0.0-preview.11 until 2.12.0 and from 3.0.0 until 3.10.0, and in Microsoft.OpenApi.Readers prior to 1.6.30, a small YAML OpenAPI document containing nested anchors and aliases can cause uncontrolled resource consumption when parsed through the public YAML reader APIs. YAML is parsed through SharpYaml, which represents aliases as shared nodes in a directed acyclic graph, so the parsed YAML graph stays small, but converting that graph to System.Text.Json.Nodes.JsonNode requires every alias to be materialized as an independent node because a JsonNode cannot be attached to multiple parents. Without a bound on that conversion work, a document with N nested anchors each referenced k times can require k^N materialized JSON nodes, leading to excessive memory allocation and process termination through out-of-memory conditions, a billion laughs style denial of service. The patched versions bound the YAML-to-JSON conversion by node count and nesting depth and report an OpenApiDiagnostic error instead of expanding without limit. This vulnerability is fixed in Microsoft.OpenApi.YamlReader 2.12.0 and 3.10.0, and Microsoft.OpenApi.Readers 1.6.30.
    Severity
    7.5 (High)
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    SSVC
    Exploitation: none Automatable: yes Technical Impact: partial
    CISA Coordinator · CISA-ADP (v2.0.3)
    Decision recorded 2026-09-08 17:36 UTC
    CWE
    • CWE-400 - Uncontrolled Resource Consumption
    Assigner
    References
    Impacted products
    Vendor Product Version
    Microsoft OpenApi.YamlReader Affected: 2.0.0-preview.11 , < 2.12.0 (semver)
    Affected: 3.0.0 , < 3.10.0 (semver)
    		Create a notification for this product.
    Microsoft OpenApi.Readers Affected: 0 , < 1.6.30 (semver)
    		Create a notification for this product.
    Credits
    myDosGyarados
    Show details on NVD website
    To clipboard 

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                "id": "CVE-2026-72923",
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                "version": "2.0.3"
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    CVE-2026-72923 (GCVE-0-2026-72923)

    Vulnerability from cvelistv5 – Published: 2026-09-08 17:12 – Updated: 2026-09-08 17:53
    VLAI
    Title
    Microsoft.OpenApi.YamlReader/Readers vulnerable to denial of service via YAML alias expansion
    Summary
    In Microsoft.OpenApi.YamlReader from 2.0.0-preview.11 until 2.12.0 and from 3.0.0 until 3.10.0, and in Microsoft.OpenApi.Readers prior to 1.6.30, a small YAML OpenAPI document containing nested anchors and aliases can cause uncontrolled resource consumption when parsed through the public YAML reader APIs. YAML is parsed through SharpYaml, which represents aliases as shared nodes in a directed acyclic graph, so the parsed YAML graph stays small, but converting that graph to System.Text.Json.Nodes.JsonNode requires every alias to be materialized as an independent node because a JsonNode cannot be attached to multiple parents. Without a bound on that conversion work, a document with N nested anchors each referenced k times can require k^N materialized JSON nodes, leading to excessive memory allocation and process termination through out-of-memory conditions, a billion laughs style denial of service. The patched versions bound the YAML-to-JSON conversion by node count and nesting depth and report an OpenApiDiagnostic error instead of expanding without limit. This vulnerability is fixed in Microsoft.OpenApi.YamlReader 2.12.0 and 3.10.0, and Microsoft.OpenApi.Readers 1.6.30.
    Severity
    7.5 (High)
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    SSVC
    Exploitation: none Automatable: yes Technical Impact: partial
    CISA Coordinator · CISA-ADP (v2.0.3)
    Decision recorded 2026-09-08 17:36 UTC
    CWE
    • CWE-400 - Uncontrolled Resource Consumption
    Assigner
    References
    Impacted products
    Vendor Product Version
    Microsoft OpenApi.YamlReader Affected: 2.0.0-preview.11 , < 2.12.0 (semver)
    Affected: 3.0.0 , < 3.10.0 (semver)
    		Create a notification for this product.
    Microsoft OpenApi.Readers Affected: 0 , < 1.6.30 (semver)
    		Create a notification for this product.
    Credits
    myDosGyarados
    Show details on NVD website
    To clipboard 

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